The overall objective of this project is to examine the effect of contraceptive steroids and naturally-occurring gonadal hormones on the regulation of circulating glucagon, prolactin, and parathormone in women and in female rhesus monkeys. Specific goals for the current year included determining 1) whether the changes in serum triglyceride and cholesterol concentrations produced by contraceptive steroids are due to changes in the molar ratio of circulating glucagon to insulin; 2) which contraceptive steroids (or combinations thereof) alter serum prolactin concentrations; and 3) whether the female rhesus monkey is a suitable primate model for studying glucose homeostasis and glucagon and parathormone physiology.